External bone-anchoring element

ABSTRACT

Broken bones are externally anchored by various embodiments of the disclosed invention. In each of the embodiments one or more arcuate members pass around the bone to be anchored. Pins extend from the arcuate members to and may also transfix the bone to be anchored. In some embodiments, there are a plurality of arcuate members. In some of the embodiments, the arcuate members encircle the bone. Various auxiliary support pieces are attached on the arcuate members. Some of these auxiliary support pieces help anchor the arcuate members. Other of these auxiliary pieces provide additional supports for additional bone supporting pins. The pins may be held on swivel joints so that the pins may be swiveled for properly engaging a bone. The arcuate members are attached to support supports which enable the anchoring arcuate members to extend to other supporting elements.

This is a continuation of prior application Ser. No. 107,546, filed Dec.27, 1979 now U.S. Pat. No. 4,365,624.

BACKGROUND OF THE INVENTION

The invention relates to an external bone-anchoring element.

External anchoring of bones is an old surgical technique which was firstused a century ago. Its application has for a long time been limited tocomplicated fractures in traumatology and consequently in orthopedics,i.e. the secondary treatment of fractures, infections slow knitting ofthe bones, pseudarthroses, difficult bone-settings, etc.

External anchoring is used more particularly for long bones such as thefemur, the tibia, the humerus, the radius, the cubitus and, inparticular, the bones in the leg.

It is desirable to be able to extend the use of the external anchoringmeans to the pelvic basin, the clavicle, to joints such as the knee,elbow and shoulder, and to the skull for the treatment of the cervicaland lumbar vertebrae, etc.

It is also desirable to manufacture small anchoring means which can beused on small bones, such as the metatarsals and the metacarpals, and inmaxillofacial surgery as well as in experimental surgery on smallanimals.

External bone-anchoring elements enable two kinds of bone-anchoring tobe carried out:

transfixing anchoring, wherein the pins extend from one side of the limbto the other, and

non-transfixing anchoring, wherein the pins are introduced into the bonewithout completely transversing it. Transfixing anchoring, which ismostly used on the leg, is more rigid than non-transfixing anchorage.

Fitted at both sides of the leg are two rods or frames which areanchored on two groups of pins disposed on either side of the fracture.The two frames or the two rods are interconnected by a brace which is asstable as possible and which may comprise sliding rods or bars, thelength of which can be increased or reduced.

External anchoring means made up of rings are also in existence. Suchanchoring means are described for example in Swiss Patent Nos. 579,385and 596,826 which relates to the use of external anchoring means usingthe "Russian" method. The anchoring means described in these two patentsare based solely on the use of circles. These are therefore the circleswhich form the frames and the braces. These circles can be single ordouble, i.e. they may surround the bone. It is thought that the singlecircle will be mostly used if there are two groups of parallel pins oneach bone fragment. In certain cases, a different problem arises. If thebone fragment is very short, i.e. near a joint, and the fragment is notlong enough to allow two or three parallel pins to be secured, use maybe made of another method, such as that described by the Russians, inwhich method a very short bone fragment can be anchored by providing acircular support on which are secured smooth transfixing intersectingpins (see Swiss Patent No. 579,385). This patent discloses a device forinterconnecting the various rings. But this device is very complicatedin its manipulation and it, therefore, does not permit the fracture tobe readily set.

Another manufacturer, Kronner, uses a plastic, circular arrangment ofwhich parallel transfixing pins are fitted. This device is alsodifferent to use since the pins are offset in relation to the circle.Setting is rendered easier, since the connecting bars are mounted onswivel joints. However, based upon tests that have been performed, theinventor hereof, the immobilizing system using swivel-joints may permitsliding after setting.

All these systems have one point in common, i.e. that of enabling thebone fragments to be moved away or towards each other as required(retraction of compression).

As a general rule, anchoring means based solely on the use of circlescan be extended to apply to the clavicle only with difficulty.

SUMMARY OF THE INVENTION

The present invention seeks to obviate the above described disadvantagesand to provide an external bone anchoring element which can be used incombination with existing frames and braces, so that the uses of theanchoring device can thus be extended.

In accordance with a first aspect of the invention, there is provided anexternal bone-anchoring element comprising at least one arcuate memberof polygonal cross-section and support pieces adapted to enable pins orwires, which retain at least one piece of bone, and/or rods, to besecured on the arcuate member.

Assembly pieces may be provided for securing the ends of the arcuatemember to the external anchoring means of which the member is acomponent part.

In one embodiment of the invention, the support pieces and/or theassembly pieces comprise jaws having internal recesses adapted tocomplement at least a portion of the periphery of the arc so as to becapable of being pressed on to and immobilized on the arc without beingable to rotate about it.

Each assembly piece and/or each support piece has a bore into which therod, pin or wire is introduced. The bore may be provided with a sleeveor lining adapted to match the diameter of the wires and pins to thebore of the piece. The bore may be so disposed that its axis extendsradially of the arc when the piece is secured thereto, or in such mannerthat its axis is perpendicular to the plane of the arc when the piece issecured.

The assembly piece may have a part pivoting about a clamping screw andrelative to the piece as a whole. The pivoting part comprises the bore,and the pivoting part may be formed by a clamp which comprises a boreand a slot.

The invention also seeks to provide an external bone-anchoring meanscomprising the anchoring element in the form of at least one arcuateportion.

In accordance with a second aspect of the invention there is provided anexternal bone-anchoring means, comprising two groups of at least twopins each retaining a bone portion. The two groups of one or more pinsis interconnected by a brace and at least one arcuate member connectedto the brace adjacent a group of pins.

At least the pins of one group may be anchored at each of their ends ina clamping device, with the two clamping devices being interconnected byan arcuate portion.

At least the pins of one group may be secured in a cruciform arrangementto at least one semi-circle.

In a preferred embodiment, additional pins designed to hold additionalbone fragments in position are secured to the circle with the aid ofadequate means adapted to position the additional fragments laterally inrelation to the circle.

The preferred cross-sectional shape of the arc is triangular. However,it could be square or of general polygonal shape. For practical reasons,the triangular cross-section is preferred because of its rigidity andthe possibility of securing the support and assembly pieces in a simplemanner, which enables a large number of different forms of assembly tobe used.

In order that the invention may be better understood, severalembodiments thereof will now be described by way of example only andwith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an external bone anchoring meanscomprising two groups of three transfixing pins each, held in positionby a frame, an element in the form of a semi-circle being mounted oneach group of pins, and bars for joining up the assembly are also shown:

FIG. 2 is a perspective view of a modified form of the anchoring meansof FIG. 1, wherein the semi-circles are used for supporting anchoringmembers carrying pins;

FIG. 3 is a side view showing a clamping piece designed to connect theend of an arcuate part to a rod;

FIG. 4 is a section along line VI--VI of FIG. 3;

FIG. 5 is a front view showing a lateral anchoring member on a circle,of the type illustrated in FIG. 2;

FIG. 6 is a side view of the FIG. 5 anchoring member;

FIG. 7 is a front view showing a radial anchoring member on an arc, ofthe type illustrated in FIG. 1;

FIG. 8 is a plan view of the anchoring member of FIG. 7;

FIG. 9 is a perspective view illustrating the fitting of a part of anexternal anchoring means, wherein a complete circle, formed by fittingtogether two semi-circles, is mounted on a group of transfixing pins,and wherein the arrangement carries connecting members for effectingconnection with another part, not illustrated, of the external anchoringmeans;

FIG. 10 is a view, likewise in perspective, of a first modified form ofthe assembly of FIG. 9, wherein the two semi-circles support radial,intersecting, transfixing pins or wires, and wherein each pin or wire issecured by its two ends of the circle;

FIG. 11 is a perspective view of a second modified form of thearrangement of FIG. 9, wherein a semi-circle carries two radialpin-halves;

FIG. 12 shows the fitting of two quarter-circles forming a semi-circle;

FIG. 13 is a front view of an arrangement comprising two quarter-circlesforming a semi-circle, wherein an anchoring device for the pins is heldat each end of the two quarter-circles;

FIG. 14 illustrates a front view of an arrangement comprising twoquarter-circles held in position by an intermediate piece, the upperportion of which has the same cross-section as that of thequarter-circles;

FIG. 15 is a front view of a quarter-circle used in the arrangementsshown in FIGS. 13 and 14;

FIG. 16 illustrates a front view of a semi-circle adapted to replace thequarter-circles, for example, as well as the intermediate assembly pieceof FIG. 14;

FIG. 17 is a transverse section through an end clamping piece for aring, on line XVII--XVII of FIG. 14, wherein the clamping piece is amodified form of the corresponding pieces shown in FIGS. 3 and 4 andwherein it is designed for use with the quarter-circles or semi-circlesof the type illustrated in FIGS. 15 and 16;

FIG. 18 is a section along line XVIII--XVIII of FIG. 14;

FIG. 19 is a cross-section through a swivel-joint which carries a pinand which is secured to a quarter-circle, this view being shown alongline XIX--XIX of FIG. 14;

FIG. 20 is a front view of a modified form of the end piece of thesemi-circles of FIGS. 13, 14 and 17;

FIG. 21 is a view along line XXI--XXI of FIG. 20;

FIG. 22 is a front view of a modified form of the FIG. 14 arrangement;

FIG. 23 is a plan view of an arrangement made up of four quarter-circlesarranged to form a ring for holding a patient's head in position and

FIG. 24 is a side view of the arrangement illustrated in FIG. 23.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The external bone-anchoring means illustrated in FIG. 1 comprising twogroups of pins 2 and 3 designed to hold and retain relatively to eachother two bone fragments 4 and 5, respectively. Each of the groups ofpins 2 and 3 comprises, respectively, three pins 6, 7, 8 and 9, 10, 11,which pass completely through the bone fragments that they are to holdin position. The pins 6-11 are called transfixing pins. Each has at oneof its ends a point 12, as illustrated in the case of the pin 6, and amedian threaded portion 13, and each has at its other end a head 14 ofsquare cross-section which enables each pin to be screwed into a bonewith the aid of a tool, not illustrated.

The pins 6, 7, 8 of group 2 and the pins 9, 10, 11 of group 3 are eachretained at their ends by anchoring clamps 15, 16 and 17, 18,respectively. Each of the clamps 15 to 18 comprises two jaws 19, 20having on their inner adjacent surfaces appropriate grooves forreceiving the pins 6 to 11. The jaws 19 and 20 forming each clamp arepressed against each other by means of two square-headed screws 21. Thejaws 19 of the clamps 15 and 16 and the jaws 19 and 20 of the clamps 17and 18 are integral, respectively, with a rod 22 disposed vertically ofthe plane of each clamp. The upper portions of the rods 22 of the jaws19 of the clamps 15 to 18 enable semi-circles 23 and 24, respectively,to be fitted. The jaws 20 of the clamps 15 and 16 are integral with arespective swivel-joint 25 designed to receive the stem of a respectiveslide bar 26. The swivel-joint 25 comprises two lateral pieces 27 and 28permitting the gripping of a central circular piece, not illustrated,that is adapted to turn about a spindle 29 and into which a stem of theslide bar 26 is introduced. The circular central piece may turn aboutthe spindle 29, and the two lateral pieces 27 and 28 are held in acircular recess, not illustrated, located within a collar 30 integralwith the jaw 20. The clamping action of the swivel-joint is achieved bymeans of a wing-nut 31.

The slide bars 26 comprises a stem 32 at the end of which is secured apiece 33 having a small roller 34 which meshes with a screw-threadedpart 35 of a second stem 36. The piece 33 is clamped to the end of thestem 32 by means of a square-headed screw 37. Provided at the end of thescrew-threaded part 35 of the stem 36 is a sliding piece 38 designed toslide on the stem 32 when the roller 34 is turned in one or otherdirection so as to lengthen or shorten the slide bar 26. The slidingpiece 38 may also be immobilized on the stem 32 by means of asquare-headed screw 39. As already mentioned above, the slide bars 26,located below the plane defined by the pins 6 to 11, are secured, on theone hand, in the swivel-joints 25 integral with the lower jaws 20 of theclamps 15 and 16 and, on the other hand, in toothed swivel-joints 40 andsecured to the stems 22 of the jaws 20 of the clamps 17 and 18. Thetoothed swivel-joints 40 each comprises two discs 41 which are appliedto each other and the adjacent surfaces of which are toothed. The outersurfaces of the discs comprise parts 42 designed to receive and retainby friction stems, for example the stems 36 of the slide bars 26 on theone hand, and on the other hand, the stems 22 of the lower jaws of theclamps 17 and 18. The toothed swivel-joints 40 are immobilized by meansof a square-headed screw 43.

The semi-circles 23 and 24 are each secured to the stems 22 of the upperjaws 19 of the clamps 15, 16, 17 and 18 with the aid of assembly pieces44 which enable the ends of the semi-circles 23 and 24 and the stem 22to be gripped by friction. The assembly pieces 44 will be described indetail hereinafter by reference to FIGS. 3 and 4. After the semi-circles23 and 24 have been positioned and immobilized on the stems 22 of theclamps 15 to 18 with the aid of the pieces 44, support pieces 25 inwhich the rods 46 are clamped are secured to said semi-circles. Thepieces 45 are support pieces adapted to be secured on the semi-circles23 and 24 and to retain the rod 46 by friction and radially of thesemi-circle, by means of a single screw 47. The pieces 45 will now bedescribed in detail with reference to FIGS. 7 and 8. Secured to the rods46 are toothed swivel-joints 40 identical to those described above, anda slide bar 26 is placed between the two swivel-joints 40 secured to therod 46.

In the embodiment of the external anchoring means which has just beendescribed, the two groups 2 and 3 of pins 6, 7, 8 and 9, 10, 11,respectively, retain two bone fragments which can be held in anyrequired position relative to each other. The two slide bars 26 locatedbelow the plane defined by the groups 2 and 3 of pins form, togetherwith the swivel-joints 25, the toothed swivel-joints 40 and the rods 22,a lower fitting. The two semi-circles 23, 24, the assembly pieces 44 and45 and the swivel-joints 40 mounted on the rods 46 and used for mountingthe upper slide bar constitute the upper fitting of the externalanchoring means of FIG. 1.

The external bone-anchoring means 1 illustrated in FIG. 1 is positionedin the following way:

The two groups 2 and 3 of pins 6, 7, 8 and 9, 10, 11, respectively, areplaced in position with the aid of a template or guide and a brace, notillustrated. Since a template is used, the pins of each of the twogroups 2 and 3 are perfectly parallel with the other pins of the groupand the pins are equidistantly spaced so that they can be introduced andclamped without difficulty between the jaws 19 and 20 of the clamps 15,16, 17 and 18. The next step is to position the lower fitting formed bythe assembly comprising the two slide bars 26 and the swivel-joints 25and 40, and the upper fitting comprising the semi-circles 23 and 24, thepieces 44 and 45, the rods 46, the swivel-joints 40 and the thirdslide-bar 26. The two pieces of bone 4 and 5 can be positioned asrequired by suitably selecting the positions of the swivel-joints 25 and40 before immobilization. On the other hand, it is possible to move thepieces of bone away from or towards each other by lengthening orshortening the slide-bars 26 by turning the rollers 34 on the bars inthe required direction. The presence of the semi-circles 23 and 24impart very great rigidity to the system.

In connection with the variant illustrated in FIG. 2, three bonefragments are to be positioned relatively to each other instead of thetwo fragments 4 and 5. An additional fragment 50 is placed between thetwo fragments 4 and 5. As shown in FIG. 2 one of the arcs, i.e. the arc23, is to carry a support element, described below, which enables thebone fragment 50 to be held in position. In this variant the two groups2 and 3 of three pins 6, 7, 8 and 9, 10, 11, respectively, are againheld in position between the jaws 19 and 20 of the clamps 15, 16, 17 and18. The rods 22 of the lower jaws 20 of the clamps 17 and 18, as in theFIG. 1 embodiment, support toothed swivel-joints 40, and the lower jaws20 of the clamps 15 and 16 carry joints with wing-nuts 25, and slidingbars 26 are placed between the joints 25 and 40 to form the lowerfitting. The rods 22 of the upper jaws 19 of the clamps 15, 16, 17 and18 carry assembly pieces 44 which enable the semi-circles 23 and 24 tobe held in position and clamped. The assembly pieces are identical tothose of FIG. 1 and will be described in detail hereinafter by referenceto FIGS. 3 and 4. Placed on the semi-circle 23 is a support piece 51which enables a rod 52 to be secured parallel to the axis of the bonefragments 4 and 5 or perpendicular to the plane of the semi-circles 23and 24. The piece 51 will be described in detail hereinafter byreference to FIGS. 5 and 6. Secured to the rod 52 is a swivel-joint 25with its clamping wingnut integral with an anchoring clamp 53 similar tothe clamps 15 to 18. Held in the clamp 53 are two pin-halves 54 and 55,the screw-threaded ends 56 and 57, respectively, of which are screwedinto the bone fragment 50 which is to be positioned between thefragments 4 and 5. As in the case of the pins 6 to 11, the pin-halves 54and 55 each have, at that end remote from that screwed into the bonefragment 50, a square-section head which enables the pin to be engagedby a wrench for screwing it on to a bone. As illustrated in FIGS. 1 and2, the pins 54 and 55 are shorter than the pins 6 to 11 which extendcompletely through the bone. Their screw-thread is provided at one oftheir ends since they are not intended to extend right through the bone.On the other hand, the pins 6 to 11 in the embodiments shown in FIGS. 1and 2 are transfixing pins and have a screw-threaded portion at theirmedian zone where they are to be retained in the bone fragments 4 and 5.In the variant shown in FIG. 2, it will be seen that the jaws of theclamps 15 to 18, as in the case of the clamp 53, have (see the clamp 18in FIG. 2) lower linings 58 and 59, the adjacent surfaces of which areprovided with grooves 60 designed to accommodate the pins. Asillustrated in the case of the clamp 18 (FIG. 2), five pairs ofcorresponding grooves 60 are provided. It is thus possible to retain oneto five pins in each clamp.

In the FIG. 2 variant, the ends of the rods of the upper jaws 19 carryclamps 17 and 18 of toothed swivel-joints 61, supporting rods 62 whichenable the upper frame of the external anchoring means to be extendedtowards the left. It will be possible to secure, on these rods 62, anyadditional retaining means considered useful, for example, a pin-half,not illustrated, similar to the halves 54 or 55 and serving to reinforcethe anchoring of the fragment 4 at the left and thus to avoid anyflexure if force is applied to this bone fragment. An additional pin ofthis kind could also be secured to the semi-circle 23 by means of asupport piece 51, a rod 52 and a clamp 53 all similar to the elementsillustrated in FIG. 2, and all extending to the left.

The advantage provided by the arc 23 and the mounting of the elements 51to 55 or any other arrangement of this type based on an arc residesmainly in the fact that the assembly can be positioned at any pointalong the arc. The fragment 50 that it supports would then be positionedwith precision and without difficulty relatively to the two other bonefragments 4 and 5. On the other hand, since the arc 23 is of triangularcross-section, the rod 52 can be very firmly anchored with the aid ofthe support piece 51 and will not become displaced. It will also beobserved that there remains, on the arc 23 as well as on the arc 24, allthe space necessary for providing other assemblies, for example, forproviding means for increasing the stability of the anchoring means as awhole, or for reinforcing the anchoring of a bone fragment in relationto the arc.

As shown in FIGS. 3 and 4, the pieces for fitting the arcs 23 and 24 onthe rods 22 enable complete stability to be established between the arcand the rest of the external anchoring means. The end 65 of each of thearcs 23 and 24 of triangular cross-section is held between twooppositely disposed part-circular grooves 66 and 67, the curvature ofwhich corresponds to that of the arcs 23 and 24 and which are formed intwo shells 68 and 69 adapted to be pressed against the arcs 23 and 24 bymeans of a square-headed screw 70. The shell 68 is extended sidewaystowards the exterior in relation to the end of the arcs 23 and 24 so asto receive a clamping element 71 having a bore 73 and a slot 72. Thebore 73 is provided for receiving the rod 22. The screw 75 extendsthrough the shell 68 as well as the clamping element 71. Thescrew-threaded part 74 permits immobilization of the rod 22 as well asthe clamping element 71 with the shell 68. As shown in FIGS. 3 and 4,the clamping element 71 and the rod 22 can pivot about the axis of thescrew 75 until the latter is tightened. The assembly piece 44, which hasbeen described by reference to FIGS. 3 and 4, is positioned with the arcin the manner described below:

The square-headed screw 70 is loosened to some extent and the two shells68 and 69 are moved away from each other. The screw 75 is also loosenedto some extent to release the clamp element 71 which opens the slot 72and this enables the rod 22 to be introduced into the bore 73. The endof the arc 23 or 24 is introduced into the grooves 66 and 67 and thescrew 70 is tightened. This causes the two shells 68 and 69 to beimmobilized on the ends of the arc. The rod 22 is then introduced intothe bore 73 of the clamp element 71, and the assembly is placed at therequired point on the rod 22. Since the clamp element 71 can pivot aboutthe axis of the screw 75, fitting on to the rod 22 will be facilitatedwhen the piece 44 is in position on the rod, and when the screw isblocked and the assembly comprising the rod 22, the assembly piece 44and the arcs 23 and 24 become rigid. If necessary, it is possible firstto place the rod 22 in the bore 73 of the clamp element 71. After that,the end 65 of the arc 23 or 24 is brought into the grooves 66 and 67 inthe shells 68 and 69. When all these parts are in position, the screws70 and 75 are tightened.

As already mentioned above, the support piece 51, illustrated in detailin FIGS. 5 and 6, enable a rod 52 to be secured perpendicularly to theplane of the arcs 23 or 24 on which it is positioned. The piece 51comprises two clamping devices 76 and 77 having two grooves 78 and 79suitable for gripping the triangular cross-section of the arcs 23 and24. As shown in FIG. 6, the grooves 78 and 79 have the same curvature asthe arcs 23 and 24. Each clamping device 76 and 77 is provided at one ofits sides with a bore 80 and 81, respectively. The axes of these boresare in alignment when the clamping devices are placed opposite eachother. At their other sides, the clamping devices 76 and 77 areinterconnected by a square-headed screw 82. The rod 52 is introducedinto the bores 80 and 81 of the clamping devices 76 and 77,respectively, which in turn are placed on the arcs 23 and 24. It is onlyrequired to tighten the screw 82 to immobilize the clamping devices 76and 77 on the arcs 23 and 24 and, at the same time, to immobilize therod 52 by flexion.

The support piece 51, just described by reference to FIGS. 5 and 6,permits the fixing, at any point along the periphery of the arcs 23 or24, a rod 52 which extends perpendicularly from one or both sides of theplane of the arc. This rod can be used for supporting any device forretaining a fragment of bone or for any device for reinforcing thesystem as a whole or a part of the external anchoring means of which itis a component part. As already stated, the positioning of the rod 52along the arcs 23 or 24 is not limited to predetermined points. Thus,the rod can be positioned with precision along the entire arc.

As already mentioned in connection with the FIG. 1 embodiment, thesupport piece 45 illustrated in FIGS. 7 and 8 enables a rod to bepositioned radially outwardly of the arcs 23 and 24. The piece 45comprises two clamping devices 85 and 86 each having at its lower part arespective groove 87 and 88, which grooves are adapted to together gripthe arcs 23 and 24. The grooves 87 and 88 have a curvature identical tothat of the arcs 23 and 24. The clamping device 86 has a slot 89 whichdelimits two clamping tabs and the slot 89 runs into a bore 90 designedto receive the rod 46. The two clamping devices 75 and 86 areinterconnected by the square-headed screw 47, the screw-threaded portion91 of which meshes with a screw-threaded portion 92 formed in the outerclamping lug of the element 86. It can be seen from FIG. 8 thattightening of the screw 47 immobilizes, on the one hand, the twoclamping elements 85 and 86 on the arc, and on the other hand, the rod46 in the bore 90. As in the case of the support piece 51 shown in FIGS.5 and 6, the piece 45, illustrated in FIGS. 7 and 8 and just described,can be placed at any point along the arcs 23 and 24. The rod 46 that thepiece 45 is to grip can be used either as a support for any means forretaining a bone fragment, or as a support for increasing the stabilityof the external anchoring means of which it is a component part.

In the mounting means shown in FIG. 9, illustrating a part of anexternal anchoring means, a group 95 of three pins 96, 97 and 98 isanchored in two clamps 99 and 100 that are identical to the clamps 17and 18 used in the embodiment and the variant shown in FIGS. 1 and 2,respectively. Secured on the rods 101, which function like rods 22 andare integral with the jaws of the clamps, are two semi-circles 102 and103 of triangular cross-section. Assembly pieces, like those describedby reference to FIGS. 3 and 4, are used for this securement purpose. Thesemi-circles 102 and 103 are mounted on the rods 101 in such manner thattheir peripheries substantially describe a circle, the central axis ofwhich conincides with the axis of a bone fragment 104 held by the groupof pins 96 to 98. The lower rods 101 of the clamps 99 and 100 are eachprovided with a swivel-joint 105 each of which grips a slide bar 106,the free end 107 of which will be solidly connected to the other part,not illustrated in FIG. 9, of the external anchoring means. This othernonillustrated part of the external anchoring means may be similar tothe part shown in FIG. 9 or to one of the parts in the FIG. 1 embodimentor the FIG. 2 variant, or it may be similar to one of the variantsdescribed hereinafter by reference to FIGS. 10 to 22.

Secured to the arc 103 is a support piece 108, which is identical to thepiece 45 shown in FIGS. 7 and 8. The piece 108 grips a rod 109,supporting a swivel-joint 110, and a further rod 111 substantiallyparallel with the slide bars 106 and performing the same function.

Secured to the semi-circle 103 is a support piece 112 which is identicalto the piece 45 shown in FIGS. 7 and 8. In support piece 112 a pin-half113 is secured. The end of pin half 113 is screwed into the bonefragment 104. The pin-half 113 is introduced into the bore of thesupport piece 112, having a cylindrical sleeve or lining, not visible inFIG. 9, for the purpose of adapting the undersize diameter of the pin113 to suit the bore of the corresponding piece 112 which normallycorresponds to the diameter of a rod similar to the rods 101, 109, 111,etc.

The presence of the half-pin 113 in the bone fragment 104 enables thearrangement consisting of the bone and the arc to be considerablystrengthened. In effect, without the half-pin 113, the transfixing pins96, 97 and 98 would be able to flex to a quite considerable extent ifforce were applied in the vertical direction to one of the ends of thebone fragment. The expert will immediately observe that the semi-circles102 and 103 provide all the space necessary for accommodating othermeans for positioning additional bone fragments or for increasing thestability of the external anchoring means. On the other hand, since thetwo semi-circles 102 and 103 completely surround the limb, the bone ofwhich they anchor, this limb is thus enclosed and protected by theanchoring assembly.

In the first variant of the FIG. 9 assembly that is ilustrated inperspective in FIG. 10, the two semi-circles 102 and 103 are connectedat each of their ends by a single rod 115 with the aid of assemblypieces 44. Midway along the rods 115 are located swivel-joints 116 atthe ends of rods 117 designed to be secured to the second part, notillustrated, of the external anchoring means. Two transfixing pins 118and 119 form an angle of approximately 70° between them and theytraverse and hold in position a bone fragment 120. The transfixing pins118 and 119 are held against the semi-circles 102 and 103, respectively,by means of support pieces 112 identical to the corresponding piece 45shown in FIGS. 7 and 8. In FIG. 10, the sleeves or linings 121 fitted inthe bores of the pieces 112 can be seen. The pieces 112 clamp thesemi-circles 102 and 103. In FIG. 10, the support pieces 112 are sopositioned that the pin 118 extends in front of the two arcs 102 and103, whereas the pin 118 extends behind them. This method of fitting thepins 118 and 119 renders it possible to avoid crossing the pins in thebone fragment 120. The pins are thus slightly offset from each other.This offsetting, combined with the facts that the pins do not cross eachother and are firmly retained over the entire length of the bores in thepieces 112 by means of the sleeves or linings 121, enables the bonefragment 120 to be positioned in a particularly stable manner. It isnecessary to apply a very considerable force to one end of the fragment120 to cause it to shift even slightly.

In the second variant of the FIG. 9 embodiment shown in FIG. 11, thebone fragment 120 is held in position by two half-pins 122 and 123 whichare not transfixing, that is to say they do not completely pass throughthe fragment 120. The half-pins 122 and 123 are secured on thesemi-circle 103 in the same manner as in the variant shown in FIG. 10,by means of two support pieces 112 and two linings 121. The semi-circle103 is connected to the external anchoring means, not illustrated, inthe same way as in the FIG. 10 variant, with the aid of assembly pieces44, rods 115, swivel-joints 116 and rods 117.

The embodiments and variants of the assemblies described by reference toFIGS. 9, 10 and 11, i.e. the embodiments wherein a complete circle isformed by two semi-circles, lend themselves particularly to the use ofwires instead of pins or half-pins. The wires will be fitted in the sameway as the pins, for example, with the aid of the pieces 112 (FIGS. 9 to11) and sleeves or linings 121 suited to the diameter of the wires. Theinventor has developed a turnbuckle, not illustrated, which is appliedto the pieces 112 and enables the wires to be tensioned beforeimmobilizing the pieces 112 by means of screws. It is obvious that ifwires are used, they must be transfixing, i.e. they must extendcompletely through the bone or bone fragment. This is the reason whycomplete circles are particularly well suited for use with wires. Theembodiment and variant in FIGS. 1 and 2 also lend themselves to the useof wires. The wires can be tensioned between the two clamps 15, 16 and17, 18 held in position by the semi-circles 23 and 24. The turnbuckle,not illustrated, is applied to the clamp before immobilizing the screws21. The wires used will preferably be made of stainless steel.

In the embodiment shown in FIG. 12, a semi-circle is formed from twoquarter-circles 126 and 127 held together by two assembly pieces 44interconnected by a single rod 128. The FIG. 12 embodiment can replacethe two semi-circles described in connection with the embodiments andvariants of FIGS. 1 to 11. On the rod between the two assembly piecesthere can be placed a swivel-joint, not ilustrated, for example, whichwill serve, for instance, for clamping another device for increasing thestability of the external anchoring means on which the twoquarter-circles 126 and 127 are fitted, or any device for holding a bonefragment in position. On the other hand, the rod 128 may be replaced bya pin-anchoring clamp, not illustrated, similar to the clamps 15 to 18used in the previously described arrangements. Each of thequarter-circles 126 and 127 can likewise be provided with any device forholding a bone fragment in position or any means designed to connect theFIG. 12 assembly to a frame of the external anchoring means, notillustrated, of which it forms a part. This can be done with the aid ofthe support pieces 45 and 51 shown in FIGS. 5 to 8. Finally, thequarter-circles 126 and 127 do not necessarily have to be used together.The fitting of a single quarter-circle where needed can readily beimagined. The quarter-circle 126 would then be provided with twoassembly pieces 44 at each of its ends, or with a piece 44 and asupport, piece 45 or 51 as in FIGS. 5 to 8, or even simply with supportpieces 45 or 51, and the quarter-circle would be connected to anexternal anchoring means, not illustrated.

In the FIG. 13 arrangement, two quarter-circles 130 have at their endsassembly pieces 131 illustrated in section in FIG. 17. The assemblypieces 131 make it possible to connect the ends of the arcs 130 veryfirmly to rods 133 with the aid of screws 132. Each of the rods 133 isconnected to a jaw of an anchoring clamp 134 identical to the clamps 15to 18 in the embodiment and variants shown in FIGS. 1, 2 and 9. Theclamps 132 serve to anchor groups of pins 135 and 137, respectively,which hold a bone fragment 136 in position. The quarter-circles 130 areillustrated in detail in FIG. 15 and have at their ends holes 138 intowhich are passed the screws 132 (FIG. 13) of the assembly pieces 131.The two quarter-circles 130 can clearly be replaced by a semi-circle 139such as illustrated in FIG. 16. The semi-circle 139 also has at its endstwo holes 138 which will enable the screws 132 to be fitted and theassembly pieces 131 to be fixed.

In the FIG. 14 arrangement which represents a variant of the FIG. 13arrangement, two quarter-circles 130 identical to those of FIG. 13 andconsequently to the quarter-circles illustrated in FIG. 15 are providedat their opposite ends with assembly pieces 131 screwed on to the endsof the arcs 130 with the aid of screws 132. The assembly pieces 131 arein turn fitted on rods 133 of the upper jaws of the anchoring clamps134. Firmly held in the two clamps 134 is a group of transfixing pins135 which hold a bone fragment 136 in position.

The two quarter-circles 130 are interconnected by a central piece 140shown in section in FIG. 18. Referring to the section in FIG. 18, it canbe seen that the intermediate piece 140 comprises two parts 141 and 142having interior grooves 143 and 144, respectively, enabling thetriangular ends of the arcs 130 to be gripped. It can be seen from FIG.14 that the piece 140 has the same curvature as the arcs 130. On theother hand, the parts 141 and 142 of the piece 140 have two ribs 145 and146 along their outer periphery, which ribs together form a triangularcross-section which will permit of the securing, to the piece 140, ofthe support pieces 45 illustrated in FIGS. 7 and 8, or the supportpieces 51 illustrated in FIGS. 5 and 6, or the modified forms of thesepieces, for example, the variant illustrated in FIG. 19 which will bedescribed later. The parts 141 and 142 each have a bore 147 and 148which bores are in alignment and which will permit the introduction of ascrew 149 designed to immobilize the two parts 141 and 142 of the piece140. It will be seen in FIGS. 14 and 18, that the screw-threaded part150 of the screw 149 meshes with a complementary screw-threaded portionin the bore 147 after having passed through the bore 138 at the end ofthe arc 130. With the screw 149 immobilized, the arcs 130 are retainedin a stable and firm manner in the piece 140.

The advantage of the arrangement shown in FIG. 14 and comprising twoquarter-circles 130 and the piece 140 resides in the fact that thesupport pieces, similar to those illustrated in FIGS. 5 to 8, can befitted at any selected position along the entire periphery of the arc,including the back of the piece 140. The pieces 140 are of differentlengths such that with the quarter-circles 130 they are able to formsemi-circles of different diameter. Thus, the FIG. 14 arrangement offersan extended range of uses of the quarter-circles 130.

FIG. 17 illustrates in section the assembly piece 131 which enables theends of the arcs 130 to be fitted to the rods 133 in the FIG. 13 and 14arrangements. The assembly piece 131 comprises a clamp 151, one end ofwhich has two side-faces 152 and 153 separated by a groove 154 andforming at the middle a bore 155 intended to accommodate the rod 133.The other end of the clamp 151 comprises a groove 156 intended to gripthe triangular cross-section of the quarter-circle 130 by cooperatingwith a further corresponding groove 157 formed in a cooperating clamp158. Two bores 159 and 160 are formed in the two ends of the piece 151as well as in the piece 158. The bore of the piece 158 isscrew-threaded, as is the bore associated with the side-face 153 of thepiece 151, and these two bores are designed to accommodate thescrew-threaded parts of the screws 132. Examination of FIG. 17 willimmediately show that the tightening of the two screws 132 will causeimmobilization of the rod 133 on the one hand, and immobilization of thequarter-circle 130 between the pieces 151 and 158, the screw 132extending through the bore 138 of the quarter-circle 130.

Secured to the quarter-circle 130 located to the left in the FIG. 14arrangement is a support clamp 161 provided with a swivel-joint anddesigned to position a rod 162 used for reinforcing the anchorage of thebone fragment 136 achieved with the aid of a group of pins 135. Thesupport piece 161 illustrated in section in FIG. 19 comprises two parts163 and 164 having grooves 165 and 166, respectively, designed to gripthe triangular cross-section of the quarter-circle 130. The part 164 hasa small circular collar 167 terminating in a frusto-conical portion 168.The collar 167 and the frusto-conical portion 168 cooperate with acomplementary female piece 169 on which is mounted an extension 170.Formed in the extension 170 is a bore 171 in which is provided a liningor sleeve 172 designed to match the diameter of the pin 162 to that ofthe bore. The entire piece 161, i.e. the parts 163 and 164, the collar167 and its frusto-conical extension 168, and the corresponding piece169 as well as the lining 167, can be immobilized by a single screw 173.The frusto-conical part 168 as well as the corresponding female part ofthe piece 169 forms an angle of a few degrees so that the swivel-jointformed by the pieces 167, 168 and 169 is completely immobilized when thescrew 178 is tightened to secure the piece on the quarter-circle 130.The particular purpose of the piece 161 resides in the fact that the pin162 which it carries can be turned about the axis of the screw. It isthus possible to position the pin 162 in the bone-fragment 136 preciselyat the place required.

FIGS. 20 and 21 illustrate a modified form of the assembly piece 131used in the arrangement illustrated in FIGS. 13 to 19. It has been seenthat the piece 131 enables the rods 133 (see FIGS. 13 and 14) to begripped only in one direction, that is to say that with these pieces 131the arcs in the arrangements shown in FIGS. 13 and 14 can only be fittedin a symmetrical manner. In the case where it is desired to position thearcs 130 of FIGS. 13 and 14 in such a way that, for example, the ends ofthe arcs are located at higher level on one of the rods 33 than on theother rod, it is necessary to provide a further assembly piece. For thispurpose, the assembly piece illustrated in FIGS. 20 and 21 is provided.Referring to these two Figures, the arc 130 is gripped in the grooves174 and 175 of the clamps 176 and 177, respectively. The clamps 176 and177 have a bore 178 and 179 at each of their ends. These bores areintended to receive screws 180 and 181. At their middle, the pieces 176and 177 have bores 182 and 183 into which are introduced circular pieces184 and 185. On their adjacent surfaces, the circular pieces 184 and 185have two corresponding grooves 186 and 187 adapted to grip the rod 133.It can be clearly seen from FIGS. 20 and 21 that immobilization of thescrews 180 and 181 causes the clamps 176 and 177 to be pressed againstthe quarter-circle 130 on the one hand, and compresses the rod 133 byway of the circular pieces 184 and 185, on the other hand. The modifiedform of the assembly piece shown in FIGS. 20 and 21 enables the assemblyconsisting of the piece and the quarter-circle 130 to be pivoted aboutthe rod 133, or vice versa. In the arrangement shown in FIG. 22, thequarter-circles 130 are secured to the rods 133 of the clamps 134 by wayof assembly pieces 131 as illustrated in FIG. 17, or variants of thesepieces shown in FIGS. 20 and 21. The clamps 134 serve to retain a groupof transfixing pins 135 which hold a bone fragment 136 in position. Attheir upper ends the quarter-circles 130 are connected to a rod 190 byway of two assembly pieces 131. Mounted on the rod is a swivel-joint 191similar to the toothed swivel-joint 61 shown in the embodiment andvariant illustrated in FIGS. 1 and 2. Secured in the bore of the toothedswivel-joint 191 is a pin 192 enclosed in a liner 193 which is designedto adapt the diameter of the pin 192 to suit the diameter of the bore inthe swivel-joint 191. As in the arrangements shown in FIGS. 13 and 14,the FIG. 22 arrangement enables a bone fragment 136 to be held morefirmly in position by means of an additional pin 192. Since theswivel-joint is able to turn about the rod 192 in either direction, itcan also be used for maintaining a further bone fragment adjacent thefragment 136.

In the fitting of the halo illustrated in FIGS. 23 and 24, the surroundfor the head 200 of the patient is formed by four quarter-circles 130which are identical to those ilustrated in FIG. 13 and the ends of whichare connected to bars 201, 202 and 203, 204, respectively, by means ofclamping pieces 205 illustrated in FIGS. 3 and 4, and 17 or 21. Mountedon the bars 203 and 204 are swivel-joint assembly pieces 206 which holdthe rods 207 and 208 perpendicular to the plane of the halo formed bythe assembly comprising the four quarter-circles 130. The rods 207 and208 will be secured to a jacket, not illustrated, worn by the patient,by way of a fitting consisting of bars or rods, likewise notillustrated, or by means of a fitting directly secured to the claviclesor shoulder-blades of the patient with the aid of transcutaneous pins.The head 200 of the patient will be held within the halo formed by thequarter-circles 130 by means of pointed screws 209. The point of eachscrew 209 bears on the cranial bones of the patient. The screws 209 areheld perpendicular to the quarter-circles 130 by means of the assemblypieces 45 shown in FIG. 7 into which will have been fitted a sleeve orlining similar to the lining 121 shown in FIGS. 10 and 11. The bore ofthe lining 121 has a screw-thread corresponding to the screw-thread ofthe pointed screws 209.

The above-described halo supports the weight of the head 200 of thepatient and prevents any movement of the head. It is used, for example,in the treatment of lesions of the cervical vertebrae, or in thetreatment of arthritis or scoliosis.

An arrangement similar to that just described for forming the halo mayalso be used for the treatment of lesions of the pelvis or lumbarvertebrae. In this case, the system will not necessarily be a closed oneas in the case in the arrangement shown in FIGS. 23 and 24. It can beformed from two or three quarter-circles connected to a frame comprisedof rods and an assembly member. The system and/or the frame will besecured to the iliac bone and/or to the sacro-iliac bone by means oftranscutaneous pins. It is possible for the frame mounts to be formedwith the aid of arcuate parts extending from the pelvis to the head bysecuring the system on the iliac bones, the shoulder-blades and theclavicles with the aid of transcutaneous pins in the case of lesionsextending over the entire length of the vertebral column.

In the embodiments and variants that have been described, the anchoringmeans comprise either complete circles formed from two semi-circles, orsemi-circles formed from quarter-circles with intermediate pieces. It isclear that a complete circle is also envisaged, which is of triangularcross-section and which would be used in conjunction with the assemblypieces or the support pieces. The main advantages of the embodimentsthat have been described are as follows:

The external anchoring means can be fitted either with the aid of asemi-circle which can be in one piece or constituted by twoquarter-circles, and intermediate pieces, or a complete circle which canbe in one piece or formed by two semi-circles. Thus, generally asemi-circle or a complete circle will be fitted for each bone to be heldin position, each semi-circle or complete circle forming what is calleda frame. The two frames will then be held in position by a connectingmeans which may be comprised either of slide bars or single assemblyrods. The slide bars offer the advantage of enabling the distancebetween two frames to be altered, i.e. the distance between twosemi-circles or complete circles each holding a bone fragment inposition. In a modified form, not illustrated, it is possible to mountthe two frames with the aid of the clamps 15 to 18, shown in FIG. 1, andtheir transfixing pins. The clamps are held in position by means ofslide bars or connecting rods. A single arcuate element is fitted whereit is necessary and useful. Such an arrangement can be envisaged in thecase illustrated in the FIG. 2 variant where only the arc 23 can beconsidered as being of use in view of the fact that it enables thefurther bone fragment 50 to be held in position with the aid of the rod52, the clamp 53 and the pins 54 and 55. This arrangement, comprisingonly one part-circle, can be advantageously used for example for ananchoring means which is to retain bone fragments on, for example, thepelvis or the clavicle of a human body.

In all the embodiments described, the connecting means is an existingone, and it can be used in combination with the arcuate parts. Thismeans consists of the rods, the slide bars, the anchoring clamps, theswivel-joints, etc.

The external bone-anchoring elements that have been described byreference to FIGS. 1 to 22 offer the following advances over existingsystems:

1. Conventional frames formed by clamps, pins and connecting bars joinedby the conventional means, in particular slide-bars and rods, can beused in combination with arcuate parts.

2. The fixing means enable pins or groups of pins to be located in anyplane by virtue of the arrangement of the arcs which serve as fixingmeans for pins which may extend laterally of them.

3. The fixing means enable the arcs to be adjusted vertically inrelation to soft parts.

4. The fixing means offer the possibility of securing, either on the arcor on the rods, complementary fixing means which may be transfixing orotherwise and which are located in another plane.

5. There is a possibility of providing a complete circle eithercomprised of a single piece or of semi-circles or quarter-circles.

6. There is a possibility of connecting the arcs or circlesindependently of each other, or one to the other, by means of rigid barsor slide-bars permitting adjustment of the distance between thefragments and enabling the mounting means obtained to be rendered moresolid.

7. There is a possibility of using the "Russian" technique, whichrequires complete circles for the treatment of body extremities.

The parts forming the external anchoring means that have been describedwill preferably be made of a stainless or non-corroding metal,particularly the pins, wires, swivel-joints, anchoring clamps, rods,slide bars, etc. On the other hand, the circles or arcs, as well as theassembly and support pieces designed to be secured to the circles orarcs, can be made of a light alloy particularly one based on aluminum ortitanium. The pins which extend through the soft portions of the body aswell as the bone are electrically insulated from each other and from theother parts of the anchoring means.

The advantages of the anchoring means described above are as follows:

(1) The apparatus can be assembled either with one or two arcs for eachbone fragment. It suffices to provide between the two arcs a connectingrod which, depending upon its length, can alter the distance between thetwo arcs and can therefore be used in a large number of cases with thesame size of arc.

(2) The connecting device is an existing device, i.e. either a Hoffmannswivel-joint with a slide bar, or an immobilizing unit forming thesubject matter of Swiss Pat. No. 579,438 and now commercially availablefor very small anchoring devices.

Although a preferred embodiment of this invention has been described,many variations and modifications will now be apparent to those skilledin the art, and it is therefore preferred that the instant invention belimited not by the specific disclosure herein, but only by the appendingclaims.

What is claimed is:
 1. An external bone-anchoring means comprising:twogroups of pins, each group being comprised of at least one pin, or thelike, for retaining a bone portion; first and second supporting means,each of the first and second supporting means being for supporting thepins of a respective one of the two groups of pins; at least oneassembly rod connected to each of the first and second supporting meansfor interconnecting the first and second supporting means; at least oneof the first and second supporting means comprising an arcuate member ofpolygonal cross-section connected to the assembly rod and at least onesupport piece on the arcuate member for supporting the pins of therespective group on the arcuate member, the at least one support piecebeing movably connected to the arcuate member, the connection betweenthe arcuate member and the support piece enabling the pins of that groupto be supported on the arcuate member anywhere along its length, thesupport piece comprising jaws having internal recesses adapted tocomplement at least a portion of the polygonal cross-section of thearcuate member so as to be capable of being pressed onto and immobilizedon the arcuate member without being able to rotate about it or movealong it.
 2. An external bone-anchoring means comprising:two groups ofpins, each group being comprised of at least one pin, or the like, forretaining a bone portion; first and second supporting means, each of thefirst and second supporting means being for supporting the pins of arespective one of the two groups of pins; at least one assembly rodconnected to each of the first and second supporting means forinterconnecting the first and second supporting means; at least one ofthe first and second supporting means comprising an arcuate memberconnected to the assembly rod, the arcuate member having a triangularcross-section, and at least one support piece on the arcuate member forsupporting the pins of the respective group on the arcuate member, theat least one support piece being movably connected to the arcuatemember, the connection between the arcuate member and the support pieceenabling the pins of that group to be supported on the arcuate memberanywhere along its length.
 3. An external bone-anchoring meanscomprising:two groups of pins, each group being comprised of at leastone pin, or the like, for retaining a bone portion; first and secondsupporting means, each of the first and second supporting means beingfor supporting the pins of a respective one of the two groups of pins;at least one assembly rod connected to each of the first and secondsupporting means for interconnecting the first and second supportingmeans; at least one of the first and second supporting means comprisingan arcuate member connected to the assembly rod, and further comprisinga plurality of support pieces on the arcuate member for supporting thepins of the respective group on the arcuate member, the support piecesbeing movably connected to the arcuate member, the connection betweenthe arcuate member and the support pieces enabling the pins of thatgroup to be supported on the arcuate member anywhere along its length,the arcuate member being semicircular, and the pins of the group of pinssupported by the support pieces on the semicircular arcuate member beingsecured by the support pieces in a generally cruciform arrangement tothe semicircular arcuate member.
 4. An external bone-anchoring meanscomprising:two groups of pins, each group being comprised of at leastone pin, or the like, for retaining a bone portion; first and secondsupporting means, each of the first and second supporting means beingfor supporting the pins of a respective one of the two groups of pins;at least one assembly rod connected to each of the first and secondsupporting means for interconnecting the first and second supportingmeans; at least one of the first and second supporting means comprisingan arcuate member connected to the assembly rod and at least one supportpiece on the arcuate member for supporting the pins of the respectivegroup on the arcuate member, the at least one support piece beingmovably connected to the arcuate member, the connection between thearcuate member and the support piece enabling the pins of that group tobe supported on the arcuate member anywhere along its length, thearcuate member being comprised of two sections thereof and anintermediate piece for interconnecting the two sections, at least one ofthe two sections of the arcuate member being of the arcuate length ofpart of a circle.
 5. An external bone anchoring means according to claim4, wherein each of the two sections of the arcuate member supports atleast one respective support piece along the arcuate length of therespective section of the arcuate member, a respective support piece oneach of the sections of the arcuate member being paired with a supportpiece on the other section of the arcuate member, the pins, or the like,extend between the respective paired support pieces for transfixing abone.
 6. An external bone anchoring means according to claim 5, whereinthe paired support pieces include aligned bores for receiving therespective pins or the like in them.
 7. An external bone anchoring meansaccording to claim 6, wherein the pins or the like are threaded alongtheir portion which transfixes a bone.
 8. An external bone-anchoringmeans according to claim 4, further comprising two of the support piecesbeing located at spaced apart locations along the arcuate length of eacharcuate member section; a respective pin, or the like, supported by eachof the support pieces, and each support piece supporting the respectivepin, or the like, so that the two pins both extend to and engage a bonebeing anchored from two different angular directions around the bone. 9.An external bone-anchoring means according to claim 4, wherein eachsupport piece has a bore therein into which may be introduced a pin orthe like.
 10. An external bone-anchoring means according to claim 9wherein the bore is provided with a sleeve lining therein with anopening adapted to match the diameter of the pin, or the like.
 11. Anexternal bore-containing means according to claim 9 wherein the bore isso disposed in the piece that the axis of the bore extends radially ofthe arcuate member when the piece is secured to the arcuate member. 12.An external bone anchoring means according to any of claims 8, 5 or 4,wherein the arcuate member has no discontinuities over its length andhas a uniform cross-section over its length for enabling the pins of theone group to be supported on to the arcuate member anywhere along itslength.
 13. An external bone anchoring means according to claim 12,wherein the arcuate member is of polygonal cross-section.
 14. Anexternal bone-anchoring means comprising:two groups of pins, each groupbeing comprised of at least one pin, or the like, for retaining a boneportion; first and second supporting means, each of the first and secondsupporting means being for supporting the pins of a respective one ofthe two groups of pins; at least one assembly rod connected to each ofthe first and second supporting means for interconnecting the first andsecond supporting means; at least one of the first and second supportingmeans comprising an arcuate member connected to the assembly rod, and atleast one support piece on the arcuate member, for supporting the pinsof the respective group on the arcuate member, the at least one supportpiece being movably connected to the arcuate member, the connectionbetween the arcuate member and the support piece enabling the pins ofthat group to be supported on the arcuate member anywhere along itslength, the support piece being adapted for supporting the pine or thelike at variable tilt orientations parallel to the plane of the arcuatemember.
 15. An external bone anchoring means according to claim 14,wherein the support piece is adapted for supporting the pin or the likeat various selected tilt orientations in and across the plane of thearcuate member.
 16. An external bone anchoring means according to any ofclaims 14, or 15, wherein the support piece supports the pin or the likespaced away from the plane of the arcuate member.
 17. An externalbone-anchoring means comprising:two groups of pins, each group beingcomprised of at least one pin, or the like, for retaining a boneportion; first and second supporting means, each of the first and secondsupporting means being for supporting the pins of a respective one ofthe two groups of pins; at least one assembly rod connected to each ofthe first and second supporting means for interconnecting the first andsecond supporting means; the first supporting means comprising anarcuate member connected to the assembly rod and two support pieces onthe arcuate member, the two support pieces being movably connected tothe arcuate member at spaced apart locations along the arcuate length ofthe arcuate member, with the connections between the arcuate member andthe support pieces enabling the pins of the respective one of the groupsto be supported on the arcuate member anywhere along its length, thesupport pieces supporting the respective pins, or the like, so that thetwo pins supported by the two support pieces are both capable ofextending to and engaging a bone for anchoring the bone from twodifferent angular directions around the bone.
 18. An externalbone-anchoring means according to claim 17, in which the secondsupporting means comprises a second arcuate member connected to theassembly rod and two additional support pieces on the second arcuatemember, each for supporting a respective pin, or the like, on the secondarcuate member, the two support pieces being movably connected to thesecond arcuate member at spaced apart locations along the arcuate lengthof the second arcuate member, with the connection between the secondarcuate member and the additional support pieces enabling the pins ofthe respective group of pins to be supported on the second arcuatemember anywhere along its length, the additional support piecessupporting the respective pins, so that the two pins supported by twoadditional support pieces are both capable of extending to and engaginga bone for anchoring the bone from two different angular directionsaround the bone.
 19. An external bone-anchoring means according to claim18, wherein each of the first-mentioned and additional support pieces isadapted for supporting the respective pin, or the like, spaced away fromand at variable tilt orientations parallel to the plane of therespective one of the first-mentioned and second arcuate members.
 20. Anexternal bone-anchoring means comprising:two groups of pins, each groupbeing comprised of at least one pin, or the like, for retaining a boneportion; first and second supporting means, each of the first and secondsupporting means being for supporting the pins of a respective one ofthe two groups of pins; at least one assembly rod connected to each ofthe first and second supporting means for interconnecting the first andsecond supporting means; at least one of the first and second supportingmeans comprising an arcuate member connected to the assembly rod,positioning means connected to the arcuate member and the respectivebone portion, and at least one support piece on the arcuate member forsupporting the pins of the respective group on the arcuate member, theat least one support piece being movably connected to the arcuatemember, the connection between the arcuate member and the support pieceenabling the pins of that group to be supported on the arcuate memberanywhere along its length.
 21. An external bone-anchoring meansaccording to claim 20, further comprising fitting means for connectingthe first-mentioned arcuate member to the assembly rod, the positioningmeans comprising an assembly piece on the first arcuate member andconnected to the fitting means, the connection between the fitting meansand the assembly piece being adjustable for adjusting the distancebetween the first arcuate member and the respective bone portion.
 22. Anexternal bone-anchoring means according to claim 21 in which the fittingmeans comprises a rod, the assembly piece comprising a clamping elementhaving a bore defined therein for receiving the rod and releasing meansfor releasing the clamping means for permitting the rod to be positionedin the bore.
 23. An external bone-anchoring means according to claim 22in which the assembly piece is movably supported on the first arcuatemember, the assembly piece further comprising pivoting means forpermitting the rod to pivot in relation to the first arcuate member whenthe assembly piece is moved along the first arcuate member.